First drive: 2013 Acura RDX

Bigger engine, better economy

By Graeme Fletcher, Postmedia News

Originally published: March 29, 2012

SMALL

MEDIUM

LARGE

Phoenix, Ariz. • With the premium crossover market representing the fastest-growing segment in Canada, Honda’s tinkering with the Acura RDX could be viewed as a risky proposition. In this instance, the changes to the latest model are all welcome and serve to address the misgivings some had about the outgoing vehicle.

When it was launched in Canada in 2007, the RDX acted as a harbinger of things to come. It was powered by a turbocharged four-cylinder engine that displaced just 2.3 litres. Today, blowing intake air into the engine is the flavour of the day. Yet the second-generation RDX swims against the tide it started — it’s now powered by a 3.5-litre V6.

Surprisingly, it is a move for the better. While the turbocharged engine provided plenty of jam, it got a little busy at the top end. The V6 is one seriously smooth replacement. It not only revs as freely as the four, it does so with the sort of refinement expected of the world’s largest maker of engines. In the RDX’s case, the V6 pushes 273 horsepower (up 33 hp versus the four) and 251 pound-feet of torque. While the torque value drops somewhat (by nine lb-ft), the increased horsepower more than compensates and gives the RDX surprising pop off the line. It runs to 100 kilometres an hour in 6.7 seconds and accomplishes the 80-to-120-km/h passing move in 5.6 seconds. That is an improvement of 0.7 and 0.3 seconds, respectively, over the first-generation model.

So, the V6 is faster. What about the economy advantage turbo technology boasts when it’s not blowing its vanes out? Acura addresses this aspect by including Variable Cylinder Management. Depending upon the engine load, it varies the number of operational cylinders. When the loads are high, it employs all six cylinders to provide the demanded performance.

When the load drops, the RDX runs on four of the six cylinders and, when loafing along on the highway, just three cylinders are consuming fuel. The end result is a fuel economy rating of 10.7 litres per 100 kilometres in the city and 7.3 L/100 km on the highway. That’s an improvement of one and 1.4 L/100 km, respectively, over the previous RDX. So much for the advantages of turbocharging.

To counter the noise, vibration and harshness that become a factor when the number of active cylinders changes, Acura has adopted an active noise cancelling system and active engine mounts. On the test route, the cylinder deactivation proved to be all but impossible to detect, meaning the measures are effective.

The RDX’s power is put to the pavement through a six-speed automatic transmission (picked up from the MDX). The extra gear (the outgoing RDX relied on five speeds) brings two significant advantages — first gear is lower, which accentuates the engine’s low-end pull, while the taller sixth gear eases the engine’s rev rate on the highway and contributes to the overall fuel economy. From a practical perspective, it makes the RDX feel crisper under hard acceleration and more relaxed when cruising at speed — the new model is remarkably quiet at speed. From there, the power reaches all four wheels through a system that’s proactive in nature, meaning it eliminates the need for the front wheels to slip before power is sent rearward. For example, 50% of the engine’s power is directed to the rear wheels when the RDX is launched quickly.

Once moving, the system drives just the front wheels to improve fuel economy. It works effectively but with one quibble — there is no Super Handling All-Wheel Drive (SH-AWD) extension. This gave the previous RDX the ability to send more power to the outside wheel in a corner, which improved overall stability and turn-in response. For most, this will not be the determining factor in the purchase decision, but it is a disappointing move for a company that touts technology as its ace.

With the new RDX’s wheelbase growing by 35 millimetres and the track by 32 mm, it has a bigger footprint and, consequently, better stability. Furthering the handling cause is the adoption of amplitude reactive dampers front and rear. In simple terms, the amount of damping changes with the speed and range of the body’s movement. When the body is moving slowly, the damping forces are low and the ride is comfortable. Toss the RDX into a corner and the damping firms to limit body roll and improve the dynamic response. Again, from a practical perspective, it has the desired effect — the ride is noticeably smoother when loafing along (all of the previous model’s choppiness has gone), yet there is very little body roll when the tone of the drive is cranked up.

Handling is sharpened further by the adoption of a new electrically assisted steering system that has good feel and an underlying advantage — it’s used in conjunction with the electronic stability control system to counter any wayward tendencies. For example, if the RDX begins to oversteer, the steering actively assists the driver in countering the skid. This and the stability control system make up for the loss of SH-AWD — well, almost.

As before, the RDX keys on its sportier overtones but not at the expense of luxury. The reworked cabin remains functional and classy to the eye, the materials are first-rate and the required equipment is in place, especially when equipped with the Technology package, which adds, among other things, a hard drive-based navigation system, a GPS-linked solar-sensing automatic climate control system and a power tailgate as well as a premium 10-speaker sound system. If there is a quibble, it is that blind spot monitoring in conspicuous by its absence.

The rest of the RDX is equally well done. There’s enough rear-seat room for two adults to lounge in complete comfort and 26.1 cubic feet of cargo space. Pulling a single lever drops the rear seatbacks and opens up 77 cu. ft. of space.

The RDX starts at $40,990 and tops out at $43,990 when the Technology package is along for the ride.